1. Field of the Invention
The present invention relates to a chain having a plurality of inner links having a plurality of inner plates in a width direction of the chain, and a plurality of outer links having a plurality of outer plates in the width direction of the chain, these inner and outer links being alternately and pivotably coupled together in the longitudinal direction of the chain.
2. Description of the Related Art
Bushing chains and roller chains and the like used in chain transmission mechanisms are known, which include a plurality of inner links having a plurality of inner plates in a width direction of the chain, and a plurality of outer links having a plurality of outer plates in the width direction of the chain, these inner and outer links being alternately and pivotably coupled together in the longitudinal direction of the chain. Chain transmission mechanisms having a chain guide member that makes sliding contact with the chain between sprockets are also known.
Generally, the outer plates and inner plates of bushing chains, roller chains and the like are both oval-shaped. These outer plates or inner plates make sliding contact with the chain guide member along the edges at one end in the height direction.
For example, in a known chain such as a chain shown in Japanese Patent Application Laid-open No. 2007-107583, inner plates (inner link plates 5) are larger in the height direction than the outer plates (outer link plates 2) so that only the inner plates (inner link plates 5) make sliding contact with the chain guide member, as a result of which the overall contact area in the chain is made smaller and frictional loss is reduced.
In the known chain such as the one shown in Japanese Patent Application Laid-open No. 2012-255523, inner plates (inner link plates 112) are formed elliptical to protrude outward at the center in the longitudinal direction of the chain so as to further reduce the area where they make sliding contact with the chain guide member, as a result of which the overall contact area in the chain is made smaller and frictional loss is reduced.